Challenge 3: Troubleshooting a Device Missing From the Dropdown — Solution Walkthrough

The troubleshooting step:

Open a terminal and run adb devices directly, rather than continuing
to rely solely on Android Studio's own device dropdown.

Why this helps, per this chapter's own material:

Android Studio's device dropdown is described in this chapter as
simply a friendly UI layer over ADB (Android Debug Bridge), the actual
underlying tool both the emulator and physical devices communicate
through. Running adb devices directly shows the same raw, underlying
list of connections the IDE's own dropdown is built from — checking
this directly can reveal whether the device genuinely isn't being
detected at the ADB level at all, or whether the problem is specific
to Android Studio's own UI failing to reflect a connection that ADB
itself can actually see.

What this step reveals:

If the device appears in adb devices' own output but not in Android
Studio's dropdown, the problem is likely something specific to the
IDE (needing a restart, a stale device list) rather than the physical
USB connection or Developer Options/USB debugging settings on the
device itself. If the device is missing from adb devices too, the
problem is more likely with USB debugging not being enabled, a bad
cable, or a driver issue — genuinely below the IDE layer entirely.

WHY THIS WORKS AS AN ANSWER
------------------------------
This exercise applies this chapter's own "the dropdown is just a UI
over ADB" point to a concrete troubleshooting scenario, correctly
using the lower-level adb devices command to isolate whether the
problem is at the IDE layer or the actual device-connection layer.